The tag length is included as one of the values in the flags byte of
block 0 passed to CBC_MAC, so merely copying the first N bytes is
insufficient.
To avoid adding more sideband data to the CBC MAC software context,
pull the generation of block 0, the AAD length, and AAD padding out of
cbc_mac.c and into cryptosoft.c. This matches how GCM/GMAC are
handled where the length block is constructed in cryptosoft.c and
passed as an input to the Update callback. As a result, the CBC MAC
Update() routine is now much simpler and simply performs the
XOR-and-encrypt step on each input block.
While here, avoid a copy to the staging block in the Update routine
when one or more full blocks are passed as input to the Update
callback.
Reviewed by: sef
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D32120
- crypto_apply() is only used for reading a buffer to compute a
digest, so change the data pointer to a const pointer.
- To better match m_apply(), change the data pointer type to void *
and the length from uint16_t to u_int. The length field in
particular matters as none of the apply logic was splitting requests
larger than UINT16_MAX.
- Adjust the auth_xform Update callback to match the function
prototype passed to crypto_apply() and crypto_apply_buf(). This
removes the needs for casts when using the Update callback.
- Change the Reinit and Setkey callbacks to also use a u_int length
instead of uint16_t.
- Update auth transforms for the changes. While here, use C99
initializers for auth_hash structures and avoid casts on callbacks.
Reviewed by: cem
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D25171
This adds the CBC-MAC code to the kernel, but does not hook it up to
anything (that comes in the next commit).
https://tools.ietf.org/html/rfc3610 describes the algorithm.
Note that this is a software-only implementation, which means it is
fairly slow.
Sponsored by: iXsystems Inc
Differential Revision: https://reviews.freebsd.org/D18592
